Dental engine.



No. 654,869; Patented July 3|, I900.

F. H. BERRY;

DENTAL ENGINE.

(Application filed July 14, 1899.)

(No Model.) 2 Shoets$heet I ERS co, PHOYOLITNOY, WASMINGTON. o. c.

No. 654,869, Patented July, 3|, I900. I F. H. BERRY.

DENTAL ENGINE. (Apyli cation filed July 14, 1 899.)

2 Sheets-Sheet 2,

(No Modem 1w: mamas PETERS ca. PnuYmL-Tnm \msummou. n. c.

1 |IIIIIIIIIIIIIIIII H I erence being had to the accompanying draw- -erative position or to be turned up and held UNITED STAT -s:

FREoERioK H. BERRY, or

PATENT OFFICE.

MILWAUKEE, WISCONSIN.

DEN TAL" ENGINE. f

srn'orrronriotiformm part of Letters retent ve. 654,869, dated July 31, 1900.

l j Application filed July 14, 1899- Serial No. 7231784. (No model.)

To all whom it mag concern;

Be it known thatLFREDERIoK H. BERRY, of Milwaukee, in the county of Milwaukee and State of Wisconsin, have invented a new and useful Improvement in Dental Engines, of which the following is a description, refings, which are a part of this specification.

My invention has relation to improvements in dental engines; r 7

One of the objects of the invention is to provide an improved construction for regulating the length of theldental-engine standard in order to provide .for readily taking up inequalities in'the belt.

A further object resides in providing a spring for automatically taking up slack in the belt, in combination with means for increasing the tensionof said spring, whereby after the expansive'power of the spring under a certain compression has become exhausted, and thereby the efficiency of the spring to further take up slack in the belt impaired, said spring maybe further compressed in order to be again serviceable as a means for automatically compensating :for. slackness and unevenness in the belt. i

A further object resides in the improved construction of dental-engine head for per-' mitting the flexible arm and the tool carried thereby to be readily turned down out of opin position for operation. I

A still further object resides in the provision of an improved self-alining bearing.

With the above; and .other incidental objects in view the invention consists of the de-' vices and parts or their equivalents, as here inafter more fully set forth and claimed.

In the accompanying drawings, Figure 1 is a front elevation of' the complete device, showing the flexible arm in position for operation. Fig. 2 is an elevation at right angles to Fig. 1. Fig.3 is a central section of the upper portion of the engine, showing the head and flexible arm carried thereby in operative position. Fig. 4 is' an elevation of the upper. portion of the'engine, showing the head andthe flexible arm and other parts carried therebyadjusted downwardly out of this sleeve 54.

operative position {and Fig. 5 is an end view of one of the self-alining bearings.

yond the side of the casing and carries a se-' ries of variable-sized pulleys 44. I

Extending upwardly from the top of the motor box or casing is a supporting-column 45 for the dental-engine arms. This column is provided at its upper end with a tubular portion 46, and in the bore of this tubular portion is fitted the lower portion of the tubular post 47, an insulatingsleeve 48 being interposed between said post 47 and the tubular portion 46 of the standard, said sleeve having outwardly-flanged upper and lower ends, the flanged upper end fitting between the upper end of thetubular portion 46 and the under side of a'shoulder formed on the post 47 and the flanged lower end fitting between the lower end of the tubular portion 46 and a nut end against a flat or plane side of the rod.

(See Fig. 3.) The upper portion of the rod 50, which extends above the post 47 is threaded, as clearly shown in Fig. 3. In order to prevent therod when turned from working downwardly, said rod is intersected by a cross-pin 53, which rests on the upper end of 'the'post 47. Connected to the upper end ofthe post 47'is 'a sleeve 54', the connection being made,

preferably, byscrew-th'reads. The standard of the dental engine tits" and telescopes into gagement described the dental-engine stand- I Thelower end of the standard is providedwith a threaded opening which ing the hand-Wheel 51.

I prefer to form the dental-engine standard just referred to of two telescoping sections,

the lower section being indicated bythe numeral 55 and the upper section by the numeral 56, said lower section being the portion which fits inthe sleeve 54. Aspring 57 is arranged'in the lower section 55, and the upper lower section 55. familiar with this classof machines, the end-' end of this spring bears against the lower end of the upper section 56, while the lower end of the sprin g bears against a pin 58 or equivalent device extending across the bore of the As is well known to those less belt, which transmits rotation to the dental-engine tool, will stretch, and consequently become slack. By constructing the standard of two ,telescopingsections and arranging the spring 57 as described provision is made for automatically taking up slackin the belt, due to stretching of said belt. Inasmuch as the spring 57 constantly exerts an upward pressure on the upper section 56 of the standard said upper section is necessarily raised as soon as any slack of the belt occurs, and consequently said slack is taken up. Of course after the spring has expanded to its full limit it'can effect no further useful function in taking-up slackin the belt; but by employing the rod .50 in connection with the two-part standard and the spring referred to whenever the spring expands to its full extent then by --me rely turning said rod the spring will be upper end ofthe section 56 of the standard is a slidable sleeve 61. The upper edge of this sleeve is rounded or beveled, as clearlyshown i-n 3. vided with a shoulder 62, which limits the upward movement of the sleeve. A coiled spring .63 is confined'within the sleeve 61 and surrounds the rod 60, the end of said spring being confined between the shoulder 62' and the upper end of a collar 64, which surrounds the rod and forms'a continuation of the upper telescoping section 56. This collar 64 is provided with a shoulder which forms a stop to limit the downward movement of the sleeve 61.

- The dental-engine headis indicated by the The interior of the sleeve is pronumeral 65 and is preferably in the form of a yoke consisting of two arms merging at their lower ends into a'downwardly-extending stem 66, said arms at the point of merging being vpivoted to the upper end of the arm 59 by means of a pivot-pin 67. One of the lower corners of this stem is rounded or beveled off, as indicated by the numeral 68. The upper ends of the arms of the dental-engine head form retaining-boxes for the bearings of the shaft which imparts rotation to the dentalengine tool, and said head also carries the dental-engine armand the flexible arm or shea-th which surrounds the flexible shaft for 'drivingthe tool.

When the engine is not in operation, the dentalengine headand the parts connected thereto are in the position shown in Fig. 4that is to say, with the head extending out horizontally from the arm 59 and the dental-engine'arm and flexible arm extending downwardly in a straight line. When it is desired that the engine should operate, the dental-engine head is turned upwardlyby hand and the rounded corner 68 of the depending stem 66 is brought'into contact with the beveled upper edge of the sleeve 61, and said sleeve is moved downwardlyagainst the action of the spring 63 to the extent permitted by the shoulder of the collar 64, and the stem then passes into the slot of the arm 59. The moment the stem reaches a vertical position in this slot with its end clear of the edge of the sleeve 61 the coiled spring 63 will expand and force the sleeve 61 upwardly, so that its upper edge will surround the lower end of the stem 66, and thereby hold said stem in a locked upright position.- In order to again bring the parts to the Fig. 4 position,

tubular portion .69 being provided with ann u lar rounded beads 71 71, said beads'being the only portions of the bearings which bear against the tubes or cylinders 69.. Arranged between the inner ends of these bearings 70 is a pulley 72, said pulley being mounted fast on a long'hub 7 3, whichis arranged within the bearings 7 O. The outer end of zon'eof the tubesor cylinders is closed by means of acapnut 74, and the outer end of the other tube or cylinder 69 has connected thereto the threaded inner end of thetubular dental-em gine arm 75, which arm forms a casing or covering for a rigid shaft 76, one end of said shaft extending through the long hub'73 of the pulley and being provided with an elongated groove 7 7 which receives the inner end of pin 78, which pin extends through the pul ley and through the hub 73, and thereby unites the pulley to the hub and also to the shaft 76. The pulley 72 is connected to any of the pulleys 44 of the motor-shaft by means of the usual endless belt 78. The shaft 76 has connected to its outer end the usual flexible shaft, (not shown,) which extends to and has connected therewith the dental-engine tool, so that when the pulley 72 is rotated by means of the belt 7 8 the shaft 7 6 and the flexible shaft connected thereto, as well as the dental tool, are rotated, as is common in this class of machines. The flexible shaft for the tool is incased by the usual flexible arm or sheath 79.

'The tubes or cylinders (39 have extending upwardly from the lower portions thereof pins 80 80, said pins engaging grooves 81 81 in the tubular bearings 7 0. These pins prevent the tubular bearings 70 from rotating in the plane of the rotation of the pulley.

The bearings 70 are an important feature of my invention, inasmuch as they provide self-alining bearings for the shafts 76 of the pulley 72. If the bearing for the shaft 76 was simply formed by holes in the arms of the yoke and said holes should happen to be out of true, the shaft would necessarily also be thrown out of true. In my improved construction, however, by providing the bearing-sleeves 70, having the beads 71 there around, no matter if the bores of the cylinders 69 are not exactly true the. shafts 7 6 will nevertheless be true, inasmuch as the bearing-sleeves 7 0 will rock slightly on the beads 71 as fulera. an advantage after the machine has been put together and in use. When there is a tight pull on the belt, there is a downward strain, with a tendency to spread the arms of the yoke apart. Under these conditions if the shaft 76 had its bearings merely in openings in the ends of the yoke-arms there would necessary be a binding. In my improved construction, however, even though a tight pull on the belt should cause a downward strain on the arms of the yoke and a spreading of such arms apart, there would be no binding of the shaft, inasmuch as the bearing-sleeves 70 would rock on the beads 71 and said bearing-sleeves would therefore aline the-shaft.

What I claim as my invention is- 1. In a dental engine, the combination, of an upwardly-extending.sleeve, a dental-engine standard fitting therein, said standard havinga threaded opening at one end, and a rod having a threaded portion engaging the threaded opening, whereby as a rod is turned the standard is raised or lowered.

2. In a dental engine, the combination, of an upwardly-extending sleeve, a twopart standard, the sections thereof telescoping, and the lower section fitting in the sleeve,

and the end of said lower section having a threaded opening, a rod having a threaded portion engaging said opening, and a spring interposed between the lower end of the up- This construction also possesses per section of the standard and a fixed point of the lower section of said standard.

3. In a dental engine, the combination, of

a standard, a slotted arm fitting in the standard, a slidable sleeve surrounding the arm arm, and means acting on the sleeve in order to hold said sleeve in a position to surround the depending stem of the head, when said stem is in the slot of the arm, but permitting said sleeve to be slid out of engagement with the stem so as to allow said stem to be turned out of the slot. 7

4:. In a dental engine, the combination, of

a standard, a slotted arm having a depending reduced portion, the latter fitting the standard, a slidable sleeve surrounding the-arm and the standard, a dental-engine head pivoted to the arm and provided with a depending stem, which stem, when the head is turned upwardly, is adapted to fit in the slot of the arm, and a spring surrounding the reduced portion of the arm, and bearing at one end against a fixed portion of the sleeve and at its opposite end against the standard.

5. In a dental engine, the combination, of a standard, a slotted arm fitting in the stand ard, a slidable sleeve surrounding the arm and the standard, the upper end of said sleeve being rounded or beveled, a dental-engine head pivoted to the arm and provided with a depending stem,'-one corner of the lower end of said stem being rounded or beveled, and said stem, when the head is turned upwardly, adapted to fit in the slot of the arm, and means acting on the sleeve in order to hold said sleeve in position to surround thedepending stem of the head when said stemis in the slot of the arm, but permitting said sleeve to he slid out of engagement with the stem so as to allow said stem to be turned out of the slot. r

- 6. In a dental engine, the combination, of a dental-engine head, the arms thereof provided at their ends with tubes or cylinders,

bearing-sleeves, said sleeves extending into the tubes or cylinders, rounded beads forming normally the only points of contact between the sleeves and the bores of the cylinders, a shaft extending into the bearing-sleeves, and a pulley connected fast to the shaft.

7. In a dental engine, the combination of adental-engine head, the arms thereof provided at their ends with tubes or cylinders, bearing-sleeves, said sleeves extending into the tubes or cylinders, rounded beads forming normally the only points of contact between the sleeves and the bores of the cylinders, a shaft extending into the bearingsleeves, a pulley connected fast to the shaft, and means for preventing the bearing-sleeves ICO from turning in a direction parallel to the plane of rotation of the pulley.

8. In a dental engine, the combination, of

4' o84,ae9

a dental-engine head, the arms thereof pro-' vided at their ends with tubes or cylinders, bearing-sleeves provided with rounded beads,

said sleeves extending into the tubes or cylinders, and the rounded beads thereof contacting with the interior of said tubes or cylinders, and said bearing-sleeves also provided with grooves or recesses, a shaft extending into the bearing-sleeves, a pulley connected 10 fast to the shaft, and pins extending fromthe tubes or cylinders and engaging the grooves of the bearing-sleeves, whereby said sleeves are prevented from rotating in the same plane of rotation as the pulley.

In testimony whereof I aflix my signature 15 in presence of two witnesses. Y

. FREDERICK H. BERRY.

Witnesses:

A. L. MORSELL, ANNA V. FAUsT. 

